1. Field of the Invention
The present invention relates to a yarn producing apparatus for producing carbon nanotube yarn from carbon nanotube fibers while causing the carbon nanotube fibers to run.
2. Description of the Related Art
A known example of the yarn producing apparatus as described above includes holding means for aggregating carbon nanotube fibers pulled out from a carbon nanotube forming substrate and twisting means for twisting the carbon nanotube fibers aggregated by the holding means (see, for example, Japanese Patent Application Laid-Open Publication No. 2010-116632).
Japanese Patent No. 3954967 (FIG. 4) discloses spinnerets or nozzles for creating alignment of the suspended nanotube arrays. The spinnerets or nozzles allow a significant increase in the intensity of the extensional flow in the nanotube suspension with an accompanying increase in the degree of carbon nanotube alignment.
In the yarn producing apparatus described in Japanese Patent Application Laid-Open Publication No. 2010-116632, since a pair of rotatable rollers is used as the holding means for aggregating carbon nanotube fibers, a resistive force is not stably exerted on the carbon nanotube fibers against the running. As a result, a twisting state generated by the twisting means may become unstable and the produced carbon nanotube yarn may not have sufficient strength. In order to produce carbon nanotube yarn having sufficient strength with the spinnerets or nozzles described in Japanese Patent No. 3954967, the spinnerets or nozzles have to be replaced each time depending on a desired thickness of carbon nanotube yarn.